05 Sci-Tech

Asteroids don’t come with a warning label that they might one day hit Earth. While we don’t know of any currently on course to do so, we are finding thousands of new ones each year, and there’s always a potential that one could. We proved a viable technique for dealing with that eventuality – the DART mission successfully moved a small asteroid using a “kinetic impactor” – basically a big rod designed to push the asteroid off its trajectory. But DART had one big flaw – it was traveling in the same direction as the asteroid, and approached it from behind, eventually hitting it with an impactor launched while in orbit around it. That technique might work if we have enough warning, but would require years of orbital mechanical maneuvering to pull off. An alternative, proposed by researchers at Beihang University, is to use a new type of solar sail to deflect a potentially hazardous asteroid by hitting it head on.

Deflecting an asteroid using an impactor comes down to one simple factor – energy. The more energy transferred from the impactor to the asteroid, the more the asteroid will move. And the great thing about energy is that it increases with the square of velocity. In other words, the faster you hit something, the more energy you impart to it.

DART smashed into Dimorphos, its target asteroid at about 6 km/s – a respectable speed, but limited by the fact that it was coming from the same direction. According to the new paper, an impactor using a solar sail can come at an approaching asteroid from the opposite direction – akin to a wrong-way highway driver – and smash into its target at around 100 km/s – imparting something like 230 times the force per kilogram of impactor mass than the DART test did.

Fraser talks about how we could potentially stop a killer asteroid.

Welcome back to the Abstract! These are the studies this week that ate well, moved mountains, grew brains, and saved medieval texts.

First, scientists set out to understand why Venus doesn’t have a moon and discover even more unnerving stuff about this delightfully nightmarish planet. Then: a hidden range of primordial supermountains, a literal brain-space, and evidence of Tudor-era subterfuge.

As always, for more of my work, check out my book First Contact: The Story of Our Obsession with Aliens, or subscribe to my personal newsletter the BeX Files.

Venus is a bizarro world with a year that is shorter than its day, a surface shaped by diabolical heat and pressure, and skies soaked in sulfuric acid. Frankly, this planet is metal enough as it is, but scientists have now suggested that Venus is also a moon-eater.

For years, researchers have pondered why Venus lacks a moon, in contrast to all other planets except Mercury. One possibility is that Venus was once orbited by a primordial satellite that it ultimately tore apart and swallowed, according to a new study. And honestly, that sounds like something Venus would do. It’s in character.

A study from Tel Aviv University argues that both possibilities may be partly correct. According to the proposed reconstruction, the sect likely used the calendar during its early history, when disagreements over religious dates contributed to its separation from the Jerusalem establishment. Later, however, the system may have been abandoned because of a fundamental astronomical problem and changing political relations with the Hasmonean leadership under Alexander Jannaeus.

The research was conducted by Prof. Eshbal Ratzon of the Department of Jewish Philosophy and the Cohn Institute for the History and Philosophy of Science and Ideas at the Entin Faculty of Humanities. The findings were published in the Tarbiz Quarterly for Jewish Studies.